Golf club head

ABSTRACT

A golf club head comprises a head main body having a hollow therein and a weight member having a specific gravity more than that of the head main body. The head main body has a face portion for hitting a ball and a sole portion continuous from the face portion to form a bottom surface of the club head. The weight member is disposed in the hollow and extends in the toe-heel direction. In a vertical cross section of the club head including the sweet spot, the weight member is arranged without contacting with the face portion and the sole portion.

BACKGROUND OF THE INVENTION

The present invention relates to a hollow golf club head with a weight member therein, more particularly to an attaching structure for the weight member capable of increasing the design freedom of weight distribution of the head without deteriorating the rebound performance of the head.

U.S. Pat. No. 8,328,661 discloses a hollow golf club head comprising a cup-shaped face member and a head main body united therewith, wherein a tongue-shaped weight part extending in the toe-heel direction is cast into the head main body or welded or fixed mechanically to the head main body, and

the weight part extends upwards from the sole portion and forward into the backside cavity of the face member. Therefore, such weight part can shift the center of gravity of the head toward the club face and also toward the sole portion.

In such club head, the bending rigidity of the sole portion is increased by the weight part extending in the toe-heel direction and united with the sole portion. As a result, the head main body when hitting a ball becomes difficult to elastically deform in the sole portion. Thus, the club head experiences decreased rebound performance.

SUMMARY OF THE INVENTION

According to an aspect of the present disclosures, a golf club head is disclosed in which the design freedom of weight distribution of the head may be increased without deteriorating the rebound performance of the head.

According to the present disclosure, a golf club head may comprise

a head main body having a hollow therein, the head main body comprising a face portion for hitting a ball, and a sole portion being continuous from the face portion and defining a bottom surface of the club head, and

a weight member disposed in the hollow, the weight member extending in the toe-heel direction of the head across a vertical plane including the sweet spot of the head and being parallel with the front-back direction of the head such that, in the vertical plane, the weight member does not contact with the face portion and the sole portion.

The golf club head according to the present invention may have the following features (1)-(14):

(1) in the vertical plane, the weight member may be disposed in a corner portion between the face portion and the sole portion; (2) in the vertical plane, the centroid of a cross section of the weight member may be positioned on the face portion side of the center of gravity of the head; (3) in the vertical plane, the centroid of a cross section of the weight member may be positioned on the sole portion side of the center of gravity of the head; (4) in the vertical plane, the entirety of a cross section of the weight member may be positioned on the sole portion side of and on the face portion side of the center of gravity of the head; (5) the weight member may be spaced apart from the sole portion continuously in the toe-heel direction between both end portions of the weight member; (6) a toe-side portion and a heel-side portion of the weight member may be fixed to the head main body; (7) the head main body may comprise a crown portion being continuous from the face portion and defining a top surface of the club head, and a side portion extending between the crown portion and the sole portion, and

the weight member may comprise a toe-side end face fixed to a toe-side part of the side portion, and a heel-side end face fixed to a heel-side part of the side portion;

(8) the weight member may comprise a toe-side end fixed to a toe-side part of the sole portion, and a heel-side end fixed to a heel-side part of the sole portion; (9) the weight member may be welded to the head main body; (10) the weight member may be fixed to the head main body by the use of a screw; (11) the weight member and the head main body may be integrally formed by casting; (12) the area of the cross section of the weight member may increase toward its center in the toe-heel direction from its toe-side and from its heel-side; (13) the golf club head may comprise an adjusting mechanism for changing the position of the weight member in one of the front-back direction, up-down direction and toe-heel direction of the head; (14) the golf club head may comprise adjusting mechanisms for changing the position of the weight member in two of the front-back direction, up-down direction and toe-heel direction of the head.

Therefore, when a ball is hit at the sweet spot for example, the face portion and the sole portion may deflect flexibly. As a result, good rebound performance may be achieved.

In this application including the description and claims, dimensions, positions, directions and the like relating to the club head refer to those under a standard state of the club head unless otherwise noted.

Here, the standard state of the club head is such that the club head is set on a horizontal plane HP so that the axis of the club shaft (not shown) is inclined at the specified lie angle alpha while keeping the axis on a vertical plane, and the face forms the specified loft angle with respect to the horizontal plane HP. Incidentally, in the case of the club head alone, the center line CL of the shaft inserting hole can be used instead of the axis of the club shaft.

“Front-back direction” is a direction parallel with a straight line N projected on the horizontal plane HP, wherein the straight line N is drawn normally to the face 2 a passing through the center G of gravity of the club head.

“Toe-heel direction” is a direction parallel with the horizontal plane HP and perpendicular to the front-back direction.

“Sweet spot SS” is the point of intersection between the face 2 a and the straight line N drawn normally to the face 2 a passing the center of gravity G of the head.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a golf club head according to the present disclosure.

FIG. 2 is a cross sectional view of the golf club head shown in FIG. 1 taken along the vertical plane including the sweet spot and extending parallel with the front-back direction of the head.

FIG. 3 is a perspective view of an aft member constituting the head main body.

FIG. 4 is a front view of the aft member shown in FIG. 3.

FIG. 5 is an exploded perspective view of an aft member of a head main body in another embodiment of the present disclosure.

FIG. 6 is a cross sectional view of the aft member shown in FIG. 5.

FIG. 7 is a cross sectional view of an aft member of a head main body in a still another embodiment of the present disclosure.

FIG. 8 is a cross sectional view of a club head as a comparative example used in the comparative test descried herein.

FIG. 9 is a schematic perspective view of a lower part of a head main body in another embodiment of the present disclosure.

FIG. 10 is a cross sectional view taken along line A-A of FIG. 9.

FIG. 11 is a schematic perspective view of a lower part of a head main body in another embodiment of the present disclosure.

FIG. 12 is a cross sectional view taken along line A-A of FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of present disclosure will now be described in detail in conjunction with accompanying drawings.

Throughout all of the embodiments, the same members or portions are denoted by the same numbers or letters.

The club head 1 may comprise a face portion 2, a crown portion 3, a sole portion 4 and a side portion 5 so as to define an internal hollow (i).

The face portion 2 has a club face 2 a for hitting a ball.

The crown portion 3 is continuous from the face portion 2 and forms a top surface of the club head.

The sole portion 4 is continuous from the face portion 2 and forms a bottom surface of the club head.

The side portion 5 extends between the crown portion 3 and the sole portion 4.

The side portion 5 is connected to the face portion 2 on the toe-side and on the heel-side.

A hosel portion 6 is formed in a heel-side of the crown portion 3. The hosel portion 6 is tubular and provided with a shaft inserting hole 6 a to be fixed to a golf club shaft (not shown).

In this embodiment, the club head 1 is for a wood-type club.

The term “wood-type” is meant for at least a driver (#1 wood), brassie (#2 wood), spoon (#3 wood), baffy (#4 wood) and cleek (#5 wood). In addition, club heads having similar shapes to those wood-type club heads are included even if the number or name of the club is different from the above.

The club head 1 may be constructed for a utility club in another embodiment of the present disclosure.

The club head 1 may comprise a head main body 10 and a weight member 11.

In this embodiment, the head main body 10 is a shell structure surrounding the hollow (i) and includes the face portion 2, the crown portion 3, the sole portion 4, the side portion 5 and the hosel portion 6.

The head main body 10 may be made of one or more kinds of metal materials, for example, stainless, maraging steel, titanium alloy, magnesium alloy, aluminum alloy and the like. However, it is also possible that the head main body 10 may be partially or wholly formed by one or more kinds of fiber reinforced resins.

The head main body 10 in this example is composed of a fore member 10 a and an aft member 10 b.

The fore member 10 a includes the face portion 2. In this embodiment, as shown in FIG. 2, the fore member 10 a includes the entirety of the face portion 2 and a turnback 13 extending backwardly from the peripheral edge of the face portion 2.

The fore member 10 a may be cup-shaped. The fore member 10 a may have a cavity opened to the back of the club head. The fore member 10 a may have a rear edge 01 defined by the rear edge of the turnback 13.

The turnback 13 may form a fore part of the crown portion 3, a fore part of the sole portion 4, a toe-side fore part of the side portion 5, and a heel-side fore part of the side portion 5.

As show in FIG. 3, the aft member 10 b may constitute a part of the club head rearward of the fore member 10 a.

In this embodiment, the aft member 10 b may form an aft part of the crown portion 3, an aft part of the sole portion 4, and an aft part of the side portion 5. The aft member 10 b is cup-shaped. The aft member 10 b has a cavity opened to the front of the club head. The aft member 10 b has a front edge 02 defined by the edges of the aft parts of the portions 3, 4 and 5. In this embodiment, the aft member 10 b includes the hosel portion 6.

The aft member 10 b is, however, not limited to such arrangement.

As shown in FIG. 2, the rear edge 01 of the fore member 10 a and the front edge 02 of the aft member 10 b may be butted with each other and fixed, for example, by welding.

Such configuration of the fore member 10 a and that of the aft member 10 b is merely an example. The configuration is not limited to this example.

The weight member 11 may be disposed in the hollow (i). The material for the weight member 11 can be arbitrarily selected according to the material(s) of the head main body 10. The material is not limited to specific ones, but metal materials, e.g. stainless steel, maraging steel, titanium alloy, copper alloy, tungsten alloy and the like can be suitably used.

In this embodiment, the weight member 11 may be made of a material having a specific gravity more than that of the head main body 10.

In another embodiment of the present disclosure, the weight member 11 and the head main body 10 may be made of an identical material.

Thus, the weight member 11 and the head main body 10 may have the same specific gravity. In this case, the weight member 11 and the head main body 10 may be formed integrally by casting.

As shown in FIG. 3, the weight member 11 may extend in the toe-heel direction of the head.

It is not always necessary that the weight member 11 continuously extends over the entire range between the toe-side extreme end and the heel-side extreme end of the hollow (i).

In this embodiment, the weight member 11 may be formed in the shape of a rod that is long in the toe-heel direction as a preferred configuration therefor.

As shown in FIG. 2, in the vertical cross section of the club head including the sweet spot SS, the weight member 11 may be arranged without contacting the face portion 2 and the sole portion 4. Therefore, as is clear from FIG. 2,

a space may be formed between the weight member 11 and the face portion 2 arranged in the front-back direction, and a space may be formed between the weight member 11 and the sole portion 4 arranged in the up-down direction. These spaces are set such that, even when the head main body 10 is deformed by hitting a ball, the noncontact state of the weight member 11 can be maintained, namely, a certain degree of space is retained. For that purpose, the spaces in the nondeformed state of the head main body 10 are preferably set to be not less than 3 mm.

In this embodiment, the weight member 11 may be disposed in the hollow (i) without contacting the crown portion 3 and the side portion 5.

In the vertical cross section of the club head, the weight member 11 preferably does not contact with the head main body 10 and it may be arranged independently as if it floats in the hollow (i).

When a ball is hit at the sweet spot SS of the club face 2 a, in the vertical cross section of the club head, the face portion 2 and sole portion 4 can therefore deflect without being hindered by the weight member 11. In this embodiment, further, the crown portion 3 and the side portion 5 can flexibly deflect without being hindered by the weight member 11. Accordingly, the head main body 10 is wholly and effectively deflected when hitting a ball, and the club head 1 can exert good rebound performance. Therefore, the club head 1 can provide a long flying distance.

In the vertical cross section of the club head shown in FIG. 2, the weight member 11 is, for example, disposed so as to approach a corner portion side formed by the face portion 2 and the sole portion 4.

In this embodiment, the weight member 11 includes a part extending over the edge 01 of the fore member 10 a of the head main body 10 toward the club face. Preferably, the centroid (g) of a cross section of the weight member 11 is positioned on the face portion 2 side of and on the sole portion 4 side of the center G of gravity of the head. The entirety of the cross section of the weight member 11 is preferably positioned on the sole portion 4 side of the center G of gravity of the head. The entirety of the cross section of the weight member 11 is preferably positioned on the face portion 2 side of the center G of gravity of the head. Such club heads 1 may result in the center G of gravity of the head being positioned lower, and closer to the club face 2 a, therefore, ballistic courses (less amount of spin) preferred by, for example, advanced-level golfers can be achieved.

As shown in FIG. 4, the weight member 11 may be fixed to the head main body 10 so as to be spaced apart from the inner surface 4 i of the sole portion 4 continuously in the toe-heel direction in substance.

In this embodiment, a toe-side and a heel-the side of the weight member 11 are fixed to the head main body 10. In this embodiment, further improved rebound performance can be exerted because the weight member 11 is spaced apart from the head main body 10 not only in the vertical cross section of the club head shown in FIG. 2 but also over a wide range in the toe-heel direction.

The weight member 11 comprises a bottom surface 15 facing toward the sole portion 4 and a top surface 16 facing toward the crown portion 3.

In the front view under the standard state, for example, the top surface 16 may extend straight along the toe-heel direction in substance. As a matter of course, the top surface 16 may be inclined, and may be provided with a concave portion or a convex portion. With respect to the shape of the back surface and the like of the weight member 11, various configurations may be employed. For example, the bottom surface 15 can include a curved surface 17 swelling toward the sole portion 5. Thereby, a cross section of the weight member 11 in this embodiment (i.e. a cross section parallel with the vertical cross section of the club head shown in FIG. 2) increases to a central portion (sweet spot SS) side from the toe-side junction position and heel-side junction position with the head main body 10. Such weight member 11 can provide the center G of gravity of the head which is further lowered.

The weight member 11 in this embodiment extends in the toe-heel direction of the head to have a toe-side end 11 a and a heel-side end 11 b.

The toe-side end 11 a of the weight member 11 may be fixed to the inner surface 5 t of a toe-side part of the side portion 5. The heel-side end 11 b of the weight member 11 may be fixed to the inner surface 5 h of a heel-side part of the side portion 5. Excepting the ends 11 a and 11 b, the weight member 11 preferably does not contact with the head main body 10.

Incidentally, the boundary between the sole portion 4 and the side portion 5 can be defined as lying at a height h of 4 mm from the horizontal plane HP in the standard state as shown in FIG. 2 and FIG. 4.

In the embodiment shown in FIG. 4, each of the ends 11 a and 11 b of the weight member 11 may be fixed by welding. Accordingly, a further strong junction of the weight member 11 and the head main body 10 may be provided, and the club head 1 with excellent durability may be obtained.

FIG. 5 and FIG. 6 show another embodiment of the present disclosure.

In this embodiment, the method for attaching the weight member 11 differs from that in the embodiment shown in FIG. 1 to FIG. 4.

The weight member 11 may be fixed to the aft member 10 b of the head main body 10 by screws 22. In a toe-side part and a heel-side part of the side portion 5 of the aft member 10 b, a toe-side attaching portion 20 and a heel-side attaching portion 21 for attaching the weight member 11, respectively, may be provided.

The toe-side attaching portion 20 may be provided with a groove 24 into which the toe-side end 11 a of the weight member 11 can be inserted from the front side, and a hole 23 for inserting the screw 22 into the weight member 11.

The hole 23 penetrates in the toe-heel direction through the toe-side attaching portion 20.

The heel-side attaching portion 21 may be provided with a groove 25 into which the heel-side end 11 b of the weight member 11 can be inserted from the front side, and a hole 26 for inserting the screw 22 into the weight member 11.

The hole 26 penetrates in the toe-heel direction through the heel-side attaching portion 21.

The toe-side end 11 a and the heel-side end 11 b of the weight member 11 may be provided with screw holes 27 and 28, respectively.

The weight member 11 may be inserted in the grooves 24 and 25 of the attaching portions 20 and 21 from the front side. Thereby, the weight member 11 is temporary supported by the aft member 10 b of the head main body 10. Next, the screws 22 may be inserted through the holes 23 and 26 and fixed to the screw holes 27 and 28 of the weight member 11. FIG. 6 shows the fixed weight member 11.

In order to distribute more mass to the toe-side and heel-side of the club head 1, a material having a specific gravity more than that of the head main body 10 may be used for the screws 22. Thereby, it is possible to provide the club head 1 an increased moment of inertia.

FIG. 7 shows still another embodiment of the present disclosure.

In this embodiment, the method for attaching the weight member 11 differs from those in the embodiments shown in FIG. 1 to FIG. 6.

The weight member 11 may be fixed to the sole portion 4 of the head main body 10 by screws. The sole portion 4 of the aft member 10 b may be provided with a toe-side attaching portion 31 and a heel-side attaching portion 32 for attaching the weight member 11.

The toe-side attaching portion 31 may be formed as a convex portion projecting into the hollow (i) formed by making a dent locally in the club head's outer surface 40. The convex portion may support the toe-side end 11 a of the weight member 11 from the underside.

The heel-side attaching portion 32 may be formed as a convex portion projecting into the hollow (i) formed by making a dent locally in the club head's outer surface 40. The convex portion may support the heel-side end 11 b of the weight member 11 from the underside. Thereby, the weight member 11 may be supported by the toe-side attaching portion 31 and the heel-side attaching portion 32, and the weight member 11 does not contact with the inner surface of the sole portion 4 between them.

The toe-side attaching portion 31 and the heel-side attaching portion 32 may be provided with through holes 33 and 36, respectively.

The weight member 11 may be provided with screw holes 34 and 37 so as to continue to the holes 33 and 36. The screws 35 and 38 may penetrate through the holes 33 and 36, respectively, from the outer surface side of the sole portion 4 and be fixed to the screw holes 34 and 37.

In this embodiment, although the weight member 11 is fixed to the sole portion 4, the weight member 11 is spaced apart from the head main body 10 over a wide range including the above-mentioned vertical cross section A of the club head, therefore, the same function as in the above-mentioned embodiments can be expected.

Preferably, in the front view of the club head, the length w measured in the toe-heel direction, of a region where the weight member 11 is spaced apart from the head main body 10 is not less than 35%, preferably not less than 40%, still more preferably not less than 50% of the club head width.

Here, the club head width is a distance measured in the toe-heel direction, in the front view of the club head under the standard state, between a toe-side extreme end and a heel point positioned at a height of 22.23 mm from the horizontal plane HP.

In the above-described embodiments shown in FIGS. 6 and 7 in which the weight member 11 is attached to the head main body 10 by the use of screws, the position of the weight member 11 is substantially fixed.

However, it is also possible to construct the club head according to the present disclosure such that the position of the weight member 11 is adjustable in at least one direction, for example, a front-back direction, up-down direction or toe-heel direction of the club head.

FIGS. 9-12 show a variety of examples of such adjusting mechanism for changing the position of the weight member 11.

Hereinafter, such examples of the adjusting mechanism will be described with reference to the drawings.

For convenience' sake, an adjusting mechanism for changing the position of the weight member 11 in the front-back direction of the club head is called “front-back adjusting mechanism 50”, an adjusting mechanism for changing the position of the weight member 11 in the up-down direction of the club head is called “up-down adjusting mechanism 60”, and an adjusting mechanism for changing the position of the weight member 11 in the toe-heel direction of the club head is called “toe-heel adjusting mechanism 70”.

As to other parts than the adjusting mechanism of each of the following embodiments not described below, the descriptions made in connection with the former embodiments may be applied thereto.

FIG. 9 schematically shows a lower part of the head main body 10 of a club head as another embodiment of the present disclosure.

In this embodiment, the club head is provided with the front-back adjusting mechanism 50 and the up-down adjusting mechanism 60.

It is, of course, possible to provide either one of the front-back adjusting mechanism 50 and the up-down adjusting mechanism 60 as another embodiment of the present disclosure.

The front-back adjusting mechanism 50 comprises front-back slotted holes 51 formed in the head main body 10 so as to extend in a front-back direction of the club head, and screws 52 respectively penetrating through the front-back slotted holes 51 and fixing the weight member 11 to the head main body 10 at a desired position.

In this example, the front-back slotted holes 51 are formed in the side portion 5.

Preferably, the front-back slotted holes 51 include a toe-side front-back slotted hole 51 a disposed in a toe-side of the side portion 5, and a heel-side front-back slotted hole 51 b disposed in a heel-side of the side portion 5. Each of the front-back slotted holes 51 a and 51 b extends substantially parallel with the above-mentioned horizontal plane HP in the standard state of the club head.

Each of the screws 52 comprises a screw axis 52 a having a diameter less than the width of the front-back slotted hole 51 through which the concerned screw 52 is penetrated, and a screw head 52 b having a diameter more than the width of the same front-back slotted hole 51.

For example, the screws 52 are penetrated through the respective front-back slotted holes 51 from the outside of the head main body 10, and inserted into respective threaded holes 27 and 28 of the weight member 11. In this embodiment, a screw 52 penetrating through the toe-side front-back slotted hole 51 a is screwed into the toe-side threaded hole 27 of the weight member 11, and a screws 52 penetrating through the heel-side front-back slotted hole 51 b is screwed into the heel-side threaded hole 28 of the weight member 11. Thus, the weight member 11 may be fixed to the head main body 10 at an arbitrary position owing to the friction between the head main body 10 and the screw head 52 b of each screw 52, for example. At this time, the weight member 11 may be supported without contacting the sole portion 4 of the head main body 10.

If it is desired to change the position of the weight member 11 in the front-back direction of the club head, for example, one of the screws 52 is loosened so as not to completely fall out of the weight member 11, and

the screws 52 on both sides are moved forward or backward along the respective front-back slotted holes 51 to move the weight member 11 in the club head accordingly, together with the screws 52. Then, the screws 52 are tightened to fix the weight member 11 at a desired position. Therefore, the position of the center of gravity of the head in the front-back direction may be adjusted.

Preferably, the front-back slotted holes 51 are closed or covered with a detachable cover after adjusting the position of the weight member 11.

The up-down adjusting mechanism 60 comprises up-down slotted holes 61 formed in the head main body 10 to extend in an up-down direction of the club head, and screws 62 respectively penetrating through the up-down slotted holes 61 and fixing the weight member 11 to the head main body 10 at a desired position.

In the embodiment shown in FIG. 9, the screws 62 double as the screws 52 in the front-back adjusting mechanism 50.

In this example, the up-down slotted holes 61 are formed in the side portion 5.

Preferably, the up-down slotted holes 61 include at least one toe-side up-down slotted hole 61 a disposed in a toe-side of the side portion 5, and at least one heel-side up-down slotted hole 61 b disposed in a heel-side of the side portion 5. In the example shown in FIG. 9, more than one toe-side up-down slotted holes 61 a and more than one heel-side up-down slotted holes 61 b are provided.

If it is desired to change the position of the weight member 11 in the up-down direction of the club head, for example, one of the screws 62 is loosened so as not to completely fall out of the weight member 11, and the screws 62 on both sides are moved up or down along the respective up-down slotted holes 61 to move the weight member 11 in the club head accordingly, together with the screws 62 as shown in FIG. 10.

Then, the screws 62 are tightened to fix the weight member 11 at a desired position. Therefore, the position of the center of gravity of the head in the up-down direction may be adjusted.

In the embodiment shown in FIG. 9, the up-down slotted holes 61 are preferably arranged to extend across the front-back slotted holes 51.

In this embodiment, the position of the weight member 11 is adjustable with respect to two directions, the front-back direction and the up-down direction of the club head. Accordingly, the position of the center of gravity of the head is adjustable in the front-back direction and the up-down direction of the club head.

Preferably, the up-down slotted holes 61 are closed or covered with a detachable cover after adjusting the position of the weight member 11.

FIG. 11 schematically shows a lower part of the head main body 10 of a club head as another embodiment of the present disclosure.

In this embodiment, the club head is provided with the toe-heel adjusting mechanism 70 and the front-back adjusting mechanism 50.

It is, of course, possible to provide either one of the toe-heel adjusting mechanism 70 and the front-back adjusting mechanism 50 as another embodiment of the present disclosure.

The toe-heel adjusting mechanism 70 comprises toe-heel slotted holes 71 formed in the head main body 10 to extend in a toe-heel direction of the club head, and screws 72 respectively penetrating through the toe-heel slotted holes 71 and fixing the weight member 11 to the head main body 10 at a desired position.

In this example, the toe-heel slotted holes 71 are formed in the sole portion 4.

Preferably, the toe-heel slotted holes 71 include at least one toe-side toe-heel slotted hole 71 a disposed in a toe-side of the sole portion 4, and at least one heel-side toe-heel slotted hole 71 b disposed in a heel-side of the sole portion 4.

In this embodiment, the toe-side toe-heel slotted hole 71 a is formed on a toe-side ridge 73, and

the heel-side toe-heel slotted hole 71 b is formed on a heel-side ridge 73, wherein the ridges 73 are formed by raising the sole portion 4 locally on both sides of a central part of the sole portion 4 in the toe-heel direction.

Each of the screws 72 comprises

a screw axis 72 a having a diameter less than the width of the toe-heel slotted hole 71 through which the concerned screw 72 is penetrated, and a screw head 72 b having a diameter more than the width of the same toe-heel slotted hole 71. For example, the screws 72 are penetrated through the toe-heel slotted holes 71 from the outside of the head main body 10, and inserted into respective threaded holes 75 of the weight member 11. In this embodiment, a screw 72 penetrating through the toe-side toe-heel slotted hole 71 a is screwed into a toe-side threaded hole 75 of the weight member 11, and a screw 72 penetrating through the heel-side toe-heel slotted hole 71 b is screwed into a heel-side threaded hole 75 of the weight member 11. Thus, the weight member 11 may be fixed to the head main body 10 at an arbitrary position by pinching the head main body 10 between the screw 72 and the weight member 11. At this time, the weight member 11 may be supported without contacting the head main body 10 at least in the above-mentioned vertical plane including the sweet spot of the head, more specifically, between the toe-side ridge 73 and the heel-side ridge 73.

If it is desired to change the position of the weight member 11 in the toe-heel direction of the club head, all of the screws 72 are loosened so as not to completely fall out of the weight member 11, and the screws 72 on both sides are moved toward the toe or heel along the respective toe-heel slotted holes 71 to move the weight member 11 in the club head accordingly, together with the screws 72 as shown in FIG. 12. Then, the screws 72 are tightened to fix the weight member 11 at a desired position. Therefore, the position of the center of gravity of the head in the toe-heel direction may be adjusted.

In the example of the front-back adjusting mechanism 50 provided in the embodiment shown in FIG. 11,

the front-back slotted holes 51 extending in the front-back direction of the club head are disposed in the sole portion 4, and the screws 52 penetrate through the front-back slotted holes 51 in order to fix the weight member 11 to the head main body 10 at a desired position.

In this embodiment shown in FIG. 11, the screws 52 double as the screws 72 of the toe-heel adjusting mechanism 70.

In this embodiment, the front-back slotted holes 51 are arranged to extend across the toe-heel slotted holes 71.

In this embodiment, the position of the weight member 11 can be changed in two directions, the front-back direction and the toe-heel direction of the club head. Therefore, the position of the center of gravity of the head may be adjusted in the front-back direction and the toe-heel direction of the club head.

Preferably, the toe-heel slotted holes 71 are closed or covered with a detachable cover after adjusting the position of the weight member 11.

In the above-described examples of the adjusting mechanisms 50, 60 and 70, the slotted holes 51, 61 and 71 are employed instead of the circular through-holes 23, 26, 33 and 36 employed in the former embodiments shown in FIGS. 6 and 7.

The slotted holes 51, 61 and 71 may be considered as extending linearly. For example, in another example of the adjusting mechanism, slotted holes curved like an circular arc around an axis extending in the up-down direction may be formed in the sole portion 4 so that the weight member is movable or rotatable around the above-mentioned axis.

While description has been made of preferable examples of the adjusting mechanism, the front-back adjusting mechanism 50 is not limited to the illustrated examples. It may be embodied in various other forms as far as the position of the weight member 11 can be changed in the front-back direction of the club head.

The up-down adjusting mechanism 60 is not limited to the illustrated example. It may be embodied in various other forms as far as the position of the weight member 11 can be changed in the up-down direction of the club head.

The toe-heel adjusting mechanism 70 is not limited to the illustrated example. It may be embodied in various other forms as far as the position of the weight member 11 can be changed in the toe-heel direction of the club head.

Comparison Tests

Wood-type club heads (Ex.1-Ex.7) having specifications shown in Table 1 were produced experimentally, and the heads were tested for the rebound performance and measured for the position of the center of gravity.

Comparative example (Ref.) had a weight member 11 shown in FIG. 8, wherein the underside of the weight member 11 was firmly fixed to the inner surface of the sole portion 4 over a length of about 70 mm in the toe-heel direction. Excepting the weight members, all of the club heads had the same structure, wherein the fore member 10 a of the head main body 10 was made of a stainless CUSTOM455 having a specific gravity 7.80, and the aft member 10 b of the head main body 10 was made of a stainless CUSTOM450 having a specific gravity 7.83.

<Measurements of Properties>

The club heads were measured for:—

the depth of the center of gravity defined by the distance between the sweet spot and the center of gravity of the head; the height of the sweet spot defined by the vertical distance from the sweet spot to the horizontal plane HP in the standard state; and a moment of inertia of the head around a horizontal axis extending in the toe-heel direction passing through the center of gravity of the head.

<Rebound Performance Test>

According to the “Procedure for Measuring the velocity Ratio of a Club Head for Conformance to Rule 4-1e, Appendix II, Revision 2 (Feb. 8, 1999), United States Golf Association.”, the restitution coefficient at a center of the club face was obtained. Here, the center of the club face is a point positioned on the club face such that the horizontal distance from the point to the toe-side extreme end of the club face is equal to the horizontal distance from the point to the heel-side extreme end of the club face, and the distance in the up-down direction from the point to the uppermost end of the club face is equal to the distance in the up-down direction from the point to the lowermost end of the club face.

The results are indicated in Table 1 by an index based on the comparative example (Ref) being 100, wherein the larger value is better.

<Spin Test>

In the above-mentioned rebound performance test, the spin of the ball immediately after the launching was measured. The results are indicated in Table 1, wherein the smaller value is better.

TABLE 1 Heads Weight member Ref. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Structure (Fig. no.) 8 4 4 6 7 7 4 4 length W (mm) 0 70 70 70 50 30 70 70 section area *1 C C ITC ITC ITC ITC ITC ITC material *2 450 450 450 450 450 450 specific gravity 7.83 7.83 7.83 7.83 7.83 7.83 10 16 mass (g) 53 53 53 53 53 53 53 53 Depth of center of gravity (mm) 23 21 20.5 20.5 20.5 20.5 20.3 20.2 Sweet spot height (mm) 22.4 22.6 22.4 22.4 22.2 22.1 22.2 21.9 Moment of inertia (g sq. cm) 1180 1070 1055 1055 1065 1070 1055 1065 Rebound performance 100.0 101.2 101.2 101.2 100.5 100.2 101.5 101.7 Spin (rpm) 2800 2806 2775 2775 2749 2736 2747 2707 *1 C: The cross section area of the weight member was constant. ITC: The cross section area of the weight member was increased toward its center in the toe-heel direction. *2 450: CUSTOM450 Stainless

From the test results, it was confirmed that, in comparison with the comparative example head, the club heads according to the present invention can exert good rebound performance while maintaining the center of gravity of the head at low and shallow positions, and thereby the spin of the hit ball is reduced.

While description has been made of preferable embodiments of the present invention, the illustrated embodiments should not be construed as to limit the scope of the present invention; various modifications are possible without departing from the scope of the present invention. 

1. A golf club head comprising a head main body having a hollow therein, the head main body comprising a face portion and a sole portion extending from the face portion and defining a bottom surface of the club head, and a weight member disposed in the hollow, the weight member extending in a toe-heel direction of the head across a vertical plane including the sweet spot of the head and being substantially parallel with the front-back direction of the head such that, in the vertical plane, the weight member does not contact the face portion and the sole portion.
 2. The golf club head according to claim 1, wherein in the vertical plane, the weight member is disposed in a corner portion between the face portion and the sole portion.
 3. The golf club head according to claim 1, wherein in the vertical plane, a centroid of a cross section of the weight member is positioned on a face portion side of the center of gravity of the head.
 4. The golf club head according to claim 1, wherein in the vertical plane, a centroid of a cross section of the weight member is positioned on a sole portion side of the center of gravity of the head.
 5. The golf club head according to claim 1, wherein in the vertical plane, an entire cross section of the weight member is positioned on a sole portion side of the center of gravity of the head and on a face portion side of the center of gravity of the head.
 6. The golf club head according to claim 1, wherein the weight member is spaced apart from the sole portion continuously in the toe-heel direction between both end portions of the weight member.
 7. The golf club head according to claim 1, wherein a toe-side portion and a heel-side portion of the weight member are fixed to the head main body.
 8. The golf club head according to claim 7, wherein the head main body comprises a crown portion being continuous from the face portion and defining a top surface of the club head, and a side portion extending between the crown portion and the sole portion, and the weight member comprises a toe-side end face fixed to a toe-side part of the side portion, and a heel-side end face fixed to a heel-side part of the side portion.
 9. The golf club head according to claim 7, wherein the weight member comprises a toe-side end fixed to a toe-side part of the sole portion, and a heel-side end fixed to a heel-side part of the sole portion.
 10. The golf club head according to claim 1, wherein the area of the cross section of the weight member is increased toward its center in the toe-heel direction from its toe-side and from its heel-side.
 11. The golf club head according to claim 1, wherein the weight member is fixed to the head main body by the use of a screw.
 12. The golf club head according to claim 1, which comprises an adjusting mechanism for changing the position of the weight member in one of the front-back direction, up-down direction and toe-heel direction of the head.
 13. The golf club head according to claim 1, which comprises an adjusting mechanism for changing the position of the weight member in two of the front-back direction, up-down direction and toe-heel direction of the head.
 14. The golf club head according to claim 1, wherein The weight member is welded to the head main body.
 15. The golf club head according to claim 1, wherein the weight member and the head main body are integrally formed by casting. 